Well, we're not supposed to merge profiles into different people if there's any information at all that suggests that they're different people. Eg. if you have a profile for John Smith, he can safely be merged into any old John Smith, only if there's no other info at all (including in the history). So cases like this, where there's pretty much no information, period, besides a relationship, it's kind of hard to say...
My gut tells me to just delete it. But of course that has negative effects as well.